It is known in the art to use a vibro-impact device with ultrasound excitation (as seen in Russian patent no. 2179919) comprising a housing with a handle; a source of oscillation excitation consisting of a magnetostrictive transducer and the vibrational velocity transformer, placed with a clearance in the housing on sliding guides, with the ability of reciprocating motion and making contact to the housing through a spring; a working head with strikers aligned with the vibrational velocity transformer; and an air cooling system for the magnetostrictive transducer.
The air cooling system in such a vibro-impact device diverts the heat from the magnetostrictive transducer only. The working head with strikers, which heats up considerably during its operation, is not cooled in the instrument, which greatly reduces the time the vibro-impact device can stay in operation. Another drawback of such a device is inconsistent quality of treatment of surfaces and welded joints, which results from changes in the hold-down force exerted by the operator when pressing the strikers to the treated surface through the handle, housing, spring, and the vibrational excitation source. This occurs because the direction of the gravitational force exerted by the vibration excitation source upon the spring will vary depending on the device's spatial positioning. When the device is positioned horizontally, the weight of the vibration excitation source does not affect the force with which the strikers are pressed against the treated surface. However, when the device is positioned in a vertically upward position, which is typically the case when treating ceiling surfaces and joints, the weight of the vibrational excitation source decreases the hold-down force with which the strikers are pressed against the treated surface. In the case of the vertically downward position, the weight of the vibrational excitation source increases the hold-down force with which the strikers are pressed against the treated surface. The small size of the device and the placement of the handle directly on the housing make it difficult for the operator, under vibro-impact conditions, to keep the vibrating tool on the treated surface or the welded joint, thus accelerating the operator's fatigue.
It is also known in the art to use an ultrasound device for improved treatment of surfaces and welded joints (as seen in Ukrainian patent no. 68264), wherein the ultrasound device includes a housing with a metal sleeve installed along the sliding guides with the possibility of reciprocating motion. Inside the sleeve, using vibro-insulators, are installed an ultrasound piezoelectric transducer connected to the vibrational velocity transformer and two sensors—a sensor of the reciprocating motion in the axial direction and a temperature sensor. A pneumatic chamber with a spring is mounted in the housing co-axially with the sleeve. The sleeve is also equipped with an attachment that allows for rotation and quick removal of the working head, with strikers that are installed such that they are allowed to move freely back and forth and to contact the outer edge of the vibrational velocity transformer. Of the two handles affixed to the housing, one is capable of revolving around the housing axis while the other one is stationary.
Such a device possesses an ineffective cooling system since the heated ultrasonic transducer placed inside the sealed metal sleeve transfers the heat only from a very small area of the exterior surface by atmospheric air convection. The heated up working head with strikers has no forced cooling and cools off by ineffective atmospheric air convection only. Dust, dirt, and metal shavings covering the treated work surface interfere with visual control of the treated area during the vibro-impact treatment process, and also tend to get into small gaps between the moveable strikers and the working head, thus jamming the strikers, and stalling the vibro-impact mode operation of the device. Similar to the previously mentioned device, a drawback of this device is inconsistent quality of treatment of surfaces and welded joints. The reason behind such inconsistency is that, depending on the device's spatial positioning, the hold-down force between the vibrational velocity transformer and the strikers varies. This is due to fluctuations in the direction of the gravitational effect of the vibration excitation source upon the spring as the operator presses the strikers to the treated surface through the handle, housing, spring, sleeve with an ultrasound piezoelectric transducer, and the vibrational excitation source. The small size of the device and the placement of the handle directly on the housing make it difficult for the operator, under vibro-impact conditions, to keep the vibrating tool on the treated surface or the welded joint thus accelerating the operator's fatigue.
Ukrainian patent no. 87006, discloses a mechanism for an ultrasound device for improved treatment of surfaces and welded joints which possesses a reliable air cooling system. Discharge of the air through the openings in the working head with strikers towards the treated surface removes dirt and dust off the surface and prevents jamming the strikers in the working head due to clogging.
Nevertheless, this mechanism has significant drawbacks as well. As in the above-mentioned cases, the drawback of such a device is the inconsistent quality of treatment of surfaces and welded joints. The reason behind such inconsistency is that, depending on the device's spatial positioning, the hold-down force between the vibrational velocity transformer and the strikers varies due to fluctuations in the direction of the gravitational effect of the vibration excitation source upon the spring, as the operator presses the strikers to the treated surface through the handle, housing, spring, sleeve with the ultrasonic piezoelectric transducer, and the vibrational excitation source. In the case when the device is positioned horizontally, gravity of the vibration excitation source does not affect the force with which the strikers are pressed to the treated work surface. In the case of the vertically upward position characteristic for treating ceiling surfaces and joints, the gravity of the vibration excitation source decreases the hold-down force of the strikers. In the case of the vertically downward position, the gravity of the vibrational excitation source increases the hold-down force of the strikers. The operator needs to consider these points when changing the spatial position of the device. This encumbers the operator's job and lowers the quality of the treatment since the operator controls the hold-down force only through the position of the pin in the housing slot.
What is desired, therefore, is and ultrasound device that can overcome the various drawbacks discussed above.